The human immunodeficiency virus (“HIV”) is the causative agent for acquired immunodeficiency syndrome (“AIDS”), a disease characterized by the destruction of the immune system, particularly of CD4+ T-cells, with attendant susceptibility to opportunistic infections, and its precursor AIDS-related complex (“ARC”), a syndrome characterized by symptoms such as persistent generalized lymphadenopathy, fever and weight loss. HIV is a retrovirus; the conversion of its RNA to DNA is accomplished through the action of the enzyme reverse transcriptase. Compounds that inhibit the function of reverse transcriptase inhibit replication of HIV in infected cells. Such compounds are useful in the prevention or treatment of HIV infection in humans.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs), in addition to the nucleoside reverse transcriptase inhibitors gained a definitive place in the treatment of HIV-1 infections. The NNRTIs interact with a specific site of HIV-1 reverse transcriptase that is closely associated with, but distinct from, the nucleoside binding site on reverse transcriptase. NNRTIs, however, are notorious for rapidly eliciting resistance due to mutations of the amino acids surrounding the NNRTI-binding site (E. De Clercq, Il Famaco 54, 26-45, 1999). Failure of long-term efficacy of NNRTIs is often associated with the emergence of drug-resistant virus strains (J. Balzarini, Biochemical Pharmacology, Vol 58, 1-27, 1999). Moreover, the mutations that appear in the reverse transcriptase enzyme frequently result in a decreased sensitivity to other reverse transcriptase inhibitors, which results in cross-resistance.
WO 00117982 discloses a series of benzophenone derivatives that when administered in vivo provide compounds that are useful as inhibitors of both wild type and mutant variants of HIV reverse transcriptase. Current methods for the preparation of certain intermediates useful in the synthesis of benzophenone compounds involve multi-step processes that are difficult to perform on large-scale and therefore are unsuitable for manufacture. The present invention features a process for the preparation of intermediates that can be carried out in a single step, that involve no toxic reagents, and are suitable for large-scale manufacture.